The PASM System and Parallel Image Processing

Abstract

One way to do image processing faster is through the use of parallelism. Different modes of parallelism can be employed in a computer system. The SIMD (single instruction stream — multiple data stream) mode [9] typically uses a set of N processors, N memories, an interconnection network, and a control unit (e.g., Illiac IV [6], STARAN [5], CLIP4 [8], MPP [16]). The control unit broadcasts instructions to the processors and all active (“enabled”) processors execute the same instruction at the same time. Each processor executes instructions using data taken from a memory with which only it is associated. The interconnection network allows interprocessor communication. An MSIMD (multiple-SIMD) system is a parallel processing system which can be structured as one or more independent SIMD machines (e g., MAP [13]). The Illiac IV was originally designed as an MSIMD system [3]. The MIMD (multiple instruction stream — multiple data stream) mode [9] typically consists of N processors and N memories, where each processor can follow an independent instruction stream (e.g., C.mmp [27], Cm* [25]). As with SIMD architectures, there is a multiple data stream and an interconnection network. A partitionable SIMD/MIMD system is a parallel processing system which can be structured as one or more independent SIMD and/or MIMD machines (e.g., TRAC [17]).